1. Field of the Invention
The present general inventive concept relates to a traveling robot, and more particularly, to a traveling robot having an enhanced traveling ability to travel along an uneven surface.
2. Description of the Related Art
Generally, a robot performs dangerous, simple, repetitional, precise, large scale or great amount of works for a human. The robot is widely used in industrial, military, domestic or other fields. A traveling apparatus is essential to the robot which should move to perform a work. Thus, technologies have been being developed for the traveling apparatus of the robot, and especially, for the traveling apparatus allowing the robot to smoothly travel in the horizontal state, and thereby minimizing shaking of the robot on an uneven surface such as a traveling surface having a stair.
FIGS. 1A to 1C schematically illustrate traveling states of a conventional traveling robot. As illustrated in FIGS. 1A to 1C, a traveling robot 101 includes a housing 110, a rear wheel 130 and a traveling part 120, and travels on a traveling surface S. The rear wheel 130 is disposed in a rear side of the housing 110 in a traveling direction “d”. The rear wheel 130 rotates idly and supports the housing 110 to the traveling surface S.
The traveling part 120 includes a frame 122, two driving wheels 124, and a front wheel 126. The frame 122 is rotatably coupled with the housing 110 by a hinge part 112. The two driving wheels 124 are disposed respectively in opposite sides of the frame 122. The driving wheel 124 receives a driving force from a driving motor 124a and moves the housing 110 in the traveling direction “d.” The front wheel 126 is supported by a front side of the frame 122. The front wheel 126 is disposed to rotate idly and supports the housing 110 to the traveling surface S. Thus, the frame 122 rotates about a center of the hinge part 112 with respect to the housing 110, and accordingly, the driving wheel 124 and the front wheel 126 move together with the frame 122. A conventional traveling robot is disclosed in U.S. Pat. No. 5,350,033.
However, a traveling ability of the traveling robot 101 is decreased when the traveling robot 101 travels on a traveling surface S having an obstacle O such as a stair. As illustrated in FIG. 1A, when the traveling robot 101 crosses the obstacle O, the front wheel 126 climbs on the obstacle O. At this time, the frame 122 rotates about a center of the hinge part 112 in a direction “a.” Accordingly, the housing 110 may maintain the horizontal state.
As illustrated in FIG. 1B, when the traveling robot 101 further travels in the traveling direction “d.” the driving wheel 124 climbs on the obstacle O, and the front wheel 126 is separated from the traveling surface S. A weight center of the traveling robot 101 moves backward to be disposed in the rear wheel 130. Accordingly, the driving wheel 124 cannot have a sufficient traction force to move the traveling robot 101 forward, and the driving wheel 124 slides the traveling surface S and accordingly, the traveling robot 101 can not cross the obstacle O smoothly.
In addition, as illustrated in FIG. 1C, when the traveling robot 101 more further travels in the traveling direction “d.”, the driving wheel 124 crosses the obstacle O, and the rear wheel 130 climbs on the obstacle O. The weight center of the traveling robot 101 moves forward rapidly. Accordingly, the front wheel 126 separated from the traveling surface S may collide with the traveling surface S, the housing 110 shakes, and a position of the traveling robot 101 is changed to thereby cause traveling errors.
Especially, the traveling ability of the traveling robot 101 is further decreased when the opposite driving wheels 124 cross obstacles having different levels (heights) from the traveling surface S. Since the one front wheel 126 and the two driving wheels 124 are supported by the frame 122 to interlock each other, it is difficult for the opposite traveling wheels 124 to adapt to the different levels of the obstacles. Accordingly, the front wheel 126 becomes separated from the traveling surface S, and the sliding of the driving wheel 124 and the shaking of the housing 110 occur. Further, the traveling robot 101 unstably travels because its ability to be stuck to the traveling surface S is largely varied as the weight center of the traveling robot 101 moves.